﻿Review of the genus Laena Dejean, 1821 (Coleoptera, Tenebrionidae) from Gansu Province, China, with the description of a new species

﻿Abstract A new species of the genus Laena from Xiaolongshan in Gansu Province, China is described as Laenahuisp. nov. All Laena species known to occur in Gansu Province are reviewed, and an identification key is provided. The mitochondrial gene COI to confirm the identity of the new species, which is morphologically most similar and phylogenetically close to L.fengileana. The new species can be recognized by features of elytra and tibiae.


Introduction
The genus Laena Dejean, 1821 belongs to the tribe Laenini, subfamily Lagriinae, family Tenebrionidae, which is widely distributed in Asia, southern Europe, and southern Africa (Bouchard et al. 2021).Adults are found under loose bark, in leaf litter, in crevices of wood, or under stones in steppe, the alpine zone, and even in subdeserts, while larvae and pupae are found in rotten wood (Wei and Ren 2019a) and in soil for xerophylic species.
Southern Gansu is an important part of the Qingling Mountains, which is an important zone of species diversity in China, and four Laena species have been recorded from Gansu Province to date (Reitter 1889;Schawaller 2001Schawaller , 2008)).During an investigation into insect diversity in Xiaolongshan, Gansu Province, another undescribed Laena species was collected in southern Gansu.In this study, Laena hui sp.nov. is described and illustrated.An identification key to the five Laena species from Gansu is also provided; it is based on examined specimens.DNA barcoding has been widely used in species delimitation in insects (Hebert et al. 2004;Hajibabaei et al. 2006;Smith et al. 2007;Liu et al. 2018;Han et al. 2022;Li et al. 2022) since it was initially proposed by Hebert et al. (2003).To clarify the taxonomic status of the new species, the mitochondrial gene COI was sequenced, and a maximum-likelihood phylogenetic tree was constructed to explore the position of L. hui sp.nov. in the genus Laena.

Materials and methods
The examined Laena specimens are deposited in the China West Normal University (CWNU), the Museum of Hebei University (MHBU), and Institute of Zoology, Chinese Academy of Sciences (IZAS).The whole genomic DNA was extracted from leg and thorax muscle tissues of Laena specimens using the Ezup Column Animal Genomic DNA Purification Kit (Shanghai, China) following the manufacturer's instructions.The polymerase chain reactions (PCR) were conducted under the conditions as specified by Wei and Ren (2023).The bidirectional sequencing of mitochondrial gene COI was conducted by Sangon Biotech Co. Ltd (Shanghai, China).The new sequences were checked and edited using SeqMan v. 7.1.0and BioEdit v. 7.1.11.All the sequences were aligned and trimmed using ClustalW and trimAl v. 1.2, respectively.The best-fit model was calculated using Modelfinder based on the Bayesian information criterion.The maximum-likelihood (ML) tree was constructed using IQtree v. 1.6.8integrated in PhyloSuite v. 1.2.2 (Zhang et al. 2020) and based on default parameters values.The original ML tree was edited and visualized using FigTree v. 1.43 and Photoshop cc 2019.In total, 31 COI sequences of 17 Laena species were used for the phylogenetic analyses, including 25 previously known and the six new sequences provided in this study (Table 1).Five species of the genus Anaedus Blanchard, 1842, Hypolaenopsis Masumoto, 2001, andGrabulax Kanda, 2016 were used as outgroups.

Phylogenetic analyses
The ML tree was reconstructed based on GTR+I+G4+F model.The phylogenetic tree (Fig. 1) showed that all the Laena species form a single clade with low value support (43).The target species, L. hui sp.nov., is close to L. fengileana in the ML tree with high value support (96).

Taxonomy Tribe Laenini Seidlitz, 1895 Genus Laena Dejean, 1821
A key to five Laena species recorded from Gansu Province  Diagnosis.Based on morphological characteristics (as provided in the identification key) and the phylogenetic position in the ML tree, the new species is most similar and closest to L. fengileana.However, L. hui sp.nov.can be distinguished from L. fengileana by the following characters: body larger, length 7.1-7.7 mm (5.7-5.9 mm in L. fengileana); body surface with very short setae, elytral intervals glabrous (elytral intervals each with a row of small punctures in L. fengileana); all tibiae distinctly hooked at their inner apex, protibiae gradually broadened from base to apex (abruptly widened at base in L. fengileana; Fig. 2H); and apices of parameres rounded and constricted, lateral margins nearly straight (distinctly concave in posterior in L. fengileana).Description.Holotype (Fig. 2A-G).Body length 7.7 mm, width 3.0 mm.Body black; antennae, maxillary palpi, and legs blackish brown; dorsal surface shiny, with sparse punctures bearing short setae.
Head hexagonal, surface smooth, with dense, large punctation bearing short setae.Genae distinctly raised, surface without punctures in apical part, and sides with small punctures.Eyes ovate and prominent.Epistome trapezoidal, with anterior margin weakly emarginated; surface slightly convex at middle, with shallow, small punctures, and each lateral side with a longer seta near anterior angle.Fronto-clypeal suture indistinct, not depressed.Frons distinctive longitudinal convex at middle, with large, sparse large punctures; lateral parts depressed, with large, dense punctures.Vertex weakly convex, with large, sparse punctures on middle.Antennae slender, reaching pronotal base when directed backwards; antennomere III approximately 2.1× as long as antennomere II, the relative ratio of the length of antennomeres II-XI as follows: 0.16:0.33:0.26:0.24:0.26:0.26:0.26:0.26:0.28:0.42.
Pronotum widest at anterior 1/3, widened anteriorly and significantly convergent from anterior 1/3 to anterior margin; anterior margin slightly emarginated at middle; lateral margins neither marked nor beaded; basal margin neither bent downwards nor beaded; disc strongly convex, surface with large, sparse punctures, and distance between punctures 0.5-3.0×puncture diameter; anterior and posterior angles rounded, not produced.Prothoracic hypomera with punctures as large as those on disc, but with shorter setae.Prosternal process widest at middle and bent downwards behind coxae; surface with dense and large punctures bearing very short setae.
Elytra (Fig. 2C) elongate-oval, widest at middle, approximately 1.6× longer than wide; lateral sides arcuate; humeral angles rounded.Elytral surface smooth, with rows of punctures without striate, bearing very short setae; punctures in rows as large as those on pronotal disc; elytral intervals with few punctures nearly invisible, interval IX with three setigerous pores (one on anterior part, two on posterior part).Elytral apices significantly prolonged and with apex obtuse.
Abdomen ovoid, approximately 1.7× as long as wide.Surface convex, smooth, with punctures gradually became smaller from ventrites I-IV, bearing short setae; posterior part of ventrites IV distinctly convex transversely at posterior part before posterior margin; ventrites V with setae at posterior part longer than those on anterior part.
Legs (Fig. 2D-F) long and slender.Femora with sharp teeth near apex on inner sides; tooth on profemora rounded at apex, and meso-and metafemoral teeth acute and pointed at apex.All tibiae slender and distinctly hooked at inner apex; protibiae gradually becoming broader from base to apex, metatibiae slightly S-shaped on inner sides.
Sexual dimorphism.Female.Body length 7.1 mm, width 3.0 mm.Apex of tibiae not hooked at inner sides.
Etymology.The name of this species honors the late Prof. Jinchu Hu (China West Normal University, Nanchong City, China) who is a famous expert on the Giant Panda.Note.The specimens were collected by sifting leaf litter in a mixed forest.The paratype was preserved in 95% alcohol, and a hind leg was used to extract the whole genome.The mitochondrial gene COI of this new species is provided in Table 1.

Figure 1 .
Figure 1.The maximum-likelihood tree of Laena species based on mitochondrial gene COI.The new species is in red.

Figure 2 .
Figure 2. Laena species A-G Laena hui sp.nov., holotype A, B dorsal and ventral views C elytra D-F pro-meso-and metaleg, in ventral view G aedeagus H proleg of L. fengileana.

Figure 3 .
Figure 3.The four Laena species previously known from Gansu Province A L. bifoveolata B L. fengileana C Laena haigouica D L. langmusica.

Table 1 .
The taxa were used for phylogenetic analysis in this study.